Mark Krasberg
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Mark Krasberg avoids the worst weeks of Wisconsin's harsh winters by lighting out for sunny Antarctica. There, at the bottom of the world, the UW-Madison physics researcher is helping to build a $270 million telescope, called Ice Cube, that promises to bring into focus some of the most violent and intriguing phenomena in the universe.
"A really strange telescope," Krasberg, 43, calls it. "It's totally not normal."
Neither is seeking refuge from harsh Wisconsin winters in the Antarctic, yet scores of UW scientists representing a range of disciplines have been doing so since at least the 1950s. Most have investigated lines of inquiry involving geology, meteorology, climate change and wildlife ecology - earnest fields of study contributing to the incremental advance of science.
Ice Cube is Big Science, the kind that could bring a great leap forward in human understanding of the universe. It also represents a recent shift from looking into deep space using physical light to observing it by other means.
Krasberg likens the difference to looking at the human body with visible light, then looking at it with X-rays or magnetic resonance imaging. "You can do the same thing with the universe," he explains.
Physicists hope Ice Cube will help them come to a deeper understanding of dark matter and profound aspects of nuclear and particle physics. And like all great advances in scientific tools, it may also yield unanticipated revelations.
Funded by a $242 million National Science Foundation grant and $30 million from German and Swedish partners in the project, Ice Cube also involves contributions from universities and institutions in Belgium, Japan, New Zealand and the United Kingdom, as well as U.S. entities ranging from Penn State and the University of California-Irvine to Lawrence Berkeley National Laboratory. More than 400 people are involved in construction of the telescope and its data-analysis infrastructure.
UW-Madison is the host institution for the project. And UW physics Prof. Francis Halzen, whose proposal secured the National Science Foundation grant, is the principal investigator.
About 100 members of the project descend on South Pole Station during Austral summer - the period between November and mid-February when it is most practical to get to the pole. A skeleton crew of two or three people is in place year-round to maintain Ice Cube's computer bank and collect data. Krasberg supervises this crew from Ice Cube world headquarters, on the 200 block of West Washington Avenue.
Ice Cube will work by tracking neutrinos - high-energy elementary particles of negligible mass. Postulated in the 1930s and identified by experiments in the 1950s, neutrinos are abundant throughout the universe, travel at or near the speed of light, and can pass through planets and other matter. Says Krasberg, "You've got 10 million going through your thumb every second."
This quality makes the neutrino uniquely suited for scientific exploration. "There's only one particle that will go through the entire earth without hitting anything, and that's a neutrino," he continues. "Everything else will get stuck."
Krasberg says scientists will employ "a kind of trick" by tracking Chernenkov radiation given off when neutrinos pass through a medium, then tracing its path back toward its source. To this end, the Ice Cube project is deploying 86 strings of hypersensitive Digital Optical Modules (DOMs) deep into the Antarctic ice. Accurate to five billionths of a second, the intricate basketball-sized sensors detect these fleeting traces of neutrino evidence.
Using a hot-water drill, crews bore one and a half miles down into the ice - stopping a few hundred meters shy of the continental bedrock - and produce a 200,000-gallon column of water. Each hole takes about a day and a half to drill.
"I would not have guessed this until I joined the project," notes Krasberg. "It takes a few days for that water to freeze back. It doesn't freeze back in an hour or two."
Once frozen in place, the DOM strings are destined to remain in the ice for millennia. The lifespan of the Ice Cube neutrino observatory is expected to span decades.
The first DOM string was deployed in 2005, eight more the following year, 13 in 2007, 18 in 2008 and 19 early this year. That brings the total to 59 and keeps the project on pace for completion in 2011.
When completed, the Ice Cube project will measure one cubic kilometer in size. To get a sense of these dimensions, take a walk down State Street from the Capitol to the UW's Library Mall - a distance of about 1,000 meters. Visualize that as Ice Cube's length. Now walk back up State Street, another kilometer, to get an idea of the telescope's width. On your third 1,000-meter stroll the length of State Street, imagine you are walking straight down through ice to get a sense of Ice Cube's depth.
Ice Cube will, scientists hope, allow them to track neutrinos back to their source, and use this information to create deep-space maps and animations of phenomena like black holes, gamma ray bursts and remnants of supernovas.
Already, with almost two-thirds of Ice Cube's detectors installed, "we see about two neutrinos per hour coming from below," says Krasberg. "What we're doing is making a sky map. We're figuring out the energies and the directions. And we're looking for a source, in the universe, in the sky, of these high-energy neutrinos. Because people basically know that high-energy neutrinos exist, but nobody knows where they come from."
There are good hypotheses and theories, but neutrinos and their origins are indeed matters of vigorous debate. A Google query asking "Where do neutrinos come from?" produces 433,000 results dominated by links to physics departments, journals and doctoral theses. Among contemporary fields of scientific inquiry, tiny neutrinos are Big Science - a topic as hot as Antarctic ice is cold.
Ice Cube is not the only research initiative luring UW-Madison scientists to the bottom of the world.
Soils science Prof. Jim Bockheim has devoted more than 30 years to the study of how Antarctica's unique soils form in its glacial cycles and arid climate.
Christine Ribic, an associate professor of wildlife ecology, is investigating the impact of climate change and retreating sea ice on vulnerable Adelie penguin populations.
Emeritus geology Prof. Charles Bentley first ventured to Antarctica in 1957 and has returned 15 times, most recently in 2008. He has both an Antarctic mountain and subglacial trench named for him; he's now leading an unprecedented cross-disciplinary project to collect core samples as far as two miles into the Antarctic ice sheet. The purpose is to build a detailed climatic record spanning tens of thousands of years.
And Matthew Lazzara, a research meteorologist at the UW's Space Science and Engineering Center, leads a team that maintains a vast network of automated weather stations providing temperature, humidity, wind and barometric-pressure data used by researchers around the world.
"We're collecting data for long-term climatology research and forecasting," says Lazzara, who got his Ph.D. from the UW.
Launched in 1980 by UW atmospheric sciences Prof. Charles Stearns, the network is underwritten by the National Science Foundation. For the past 17 years, the UW's Antarctic Meteorological and Research Center has augmented data from the automated weather stations with data from geostationary and polar orbiter satellites. These resources can then be used as the foundation for numerical modeling and simulations, which Lazzara calls "a big deal for climate-change studies." They are also critical to minimizing the number of flights to, from and within Antarctica that must be aborted due to weather conditions. (Each aborted flight can cost tens of thousands of dollars.)
Lazzara's team maintains more than 60 automated weather stations in Antarctica, accounting for about half the total distributed across the continent. On the map, he allows, it looks like a lot of stations - until you consider the Antarctic is about one and a half times the size of the U.S., which has thousands of weather stations.
"There are a lot of scientists in Antarctica," says Lazzara. "We all share these resources."
While more stations are being added to the network, most of Lazzara's time in Antarctica is devoted to maintenance work. This past season, his eighth visit since 1994, he was part of a team of four.
The work is challenging. The narrow three-month window of opportunity imposes a sense of urgency to get things done, and enforces a workweek of six days - each of which can stretch to 14, 16, even 18 hours. The team relies on snowmobile or truck to get to some stations. More isolated sites require travel by helicopter or plane. Scheduling flights can involve a wait. The weather can be uncooperative.
One November, says Lazzara, "we got down to almost minus-70." And the winds can also be brutal: "I think the highest wind speed that we've measured at one of our weather stations was 137 miles an hour." To venture out in conditions like that requires layering up in heat-trapping, moisture-wicking long underwear, Polar fleece, wind pants, a big Canada goose down parka and insulated boots. Even then it's no picnic.
Krasberg notes that conditions near South Pole Station tend to be less extreme. Indeed, with the sun blazing 24 hours a day during Austral summer, in light winds and temperatures around minus-40, "you can take your gloves off," he says. But when winds kick up to 30 or 40 knots, "it's horrible," Krasberg adds. "You can't see a thing - blowing snow, you're blind, you have no visibility."
The journey from the United States to Antarctica involves a three-day endurance trial via Los Angeles and Christchurch, New Zealand, with an uncomfortable final leg of six to nine hours. Dorm accommodations cluster two or three people per room. And the perpetual sunlight can mess up travelers' sleep cycles.
Working at the bottom of the world also means being away from home for six or eight weeks, missing Thanksgiving and Christmas and New Year's Eve celebrations. This can be hard, especially for folks like Lazzara, who has two kids.
"When they were little," he confides, "I'd be away for that kind of time, they wouldn't recognize me when I came home. It took them a day or two to figure out, 'Oh, yeah, you're dad.'"
But sacrifice is balanced by a sense of mission. Almost 30 years since the UW established its first automated weather station in Antarctica, the network is on the verge of a milestone.
For much of climatology and meteorology, notes Lazzara, "30 years is the standard baseline" to begin determining weather norms. The prospect of achieving this threshold registers in his eyes and speech, both animated with enthusiasm.
Lazzara uses McMurdo Station, on the Antarctic coast, as his base. "McMurdo can be very nice," he says. "You were very cold here in January. We weren't. It's summer there. We were over 30 some days. We got close to 40 a couple times. It was fantastic. The wind was light. The sun was out all the time, 24/7."
For entertainment during downtime, he takes his iPod. The station library is sustained with books donated by the summer population of 800 to 1,100 scientists and support staff. McMurdo affords a grand view of the trans-Antarctic range. "They're like Rocky Mountain tall," he says. "It's gorgeous."
Lazzara also enjoys the transnational camaraderie he finds at McMurdo, where he's encountered scientists from Britain, China, France, India, Italy, Japan, New Zealand, Russia, South Korea and the Ukraine. "Nations that might not get along so well in the mid-latitudes get along a whole lot better in Antarctica," he observes.
There are also extraordinary experiences. Lazzara met Prince Albert of Monaco and Sir Edmund Hillary during their visits to McMurdo. And the memory of one solo hike stands out.
"This was a fairly long walk away from the station," he relates. "I happened to pick a day that was sunny and no wind. Now remember, this part of Antarctica, there wasn't a lot of biological life, penguins, that sort of thing. I stopped walking in the snow. Immense quiet. Almost pure silence."
Krasberg's own experiences in Antarctica this past season are documented in an extraordinary collection of photos, videos and blog posts on Ice Stories, a National Science Foundation website. These convey a sense of the vastness of the undertaking - the DOMs, the hot-water drilling, the lowering of strings deep into the Antarctic ice - as well as the extreme conditions and terrible beauty researchers find at the South Pole.
Born in Annapolis and raised in Houston, Texas, and Aberdeen, Scotland, Krasberg is the son of a diver for the oil business. He inherited his father's affinity for scuba, and often follows his Antarctic deployments with vacations to diving destinations like Vanuatu, Fiji and Australia's Great Barrier Reef.
Krasberg first ventured to the bottom of the world in 2005, when he joined the Ice Cube project after taking his Ph.D. from the University of Michigan. His first impressions remain crystalline. Landing at McMurdo after the flight from Christchurch, "you get off the plane and there's this active volcano that's a few miles away, towering over you, and it's got a volcanic plume coming out of it."
Another three-hour flight on a C-130 equipped with skis brings scientists to the South Pole Station. "You get off the plane," he says, "and it's cold and it's this ice desert. It's just ice as far as you can see." He describes it as "a barren wasteland." Almost everything that needs to be stored can be left outside in the arid cold, packed in cardboard boxes stacked on palettes - food, other provisions and anything else that can withstand temperatures as low as 60 degrees below zero.
Bulldozing the blowing snow is a relentless task. "The buildings are on stilts," he says, "with the idea that snow blows through, underneath the base of the buildings."
A new $200 million South Pole Station was christened last year. It can accommodate a summer population of about 250 people; that number dwindles to 40 or 50 to maintain the facility through the dark and isolated winter months.
Amenities include pool and foosball tables, weekly movies, a greenhouse and galley ("Good food is important for morale," Krasberg explains) and a gym. The altitude can make exertion "incredibly tiring."
"When I play volleyball there I'm just about keeling over," he says. "I tried playing Ultimate Frisbee once or twice, and you know, yeah, it's a lot of work. Golf - I love playing golf there." Teeing off from the South Pole marker, Krasberg and company drive orange balls to one of the grate-covered holes they've drilled. "You're talking like a thousand-yard hole. It's really fun."
